title: Response to dehydration in elderly patients in long-term care.
abstract: Elderly patients in long-term care have a high plasma osmolality (pOSM) and associated increased mortality. In these patients, we examined pOSM, thirst (visual analogue scale, VAS) and arginine vasopressin (AVP) response to 16-hour dehydration and 2-hour rehydration. Twelve patients were randomly divided into two groups (A & B). Group A had their fluid balance monitored for two weeks, group B did not. Single measurements of VAS, pOSM and AVP were conducted on days 0, 7 and 13. Dehydration tests were conducted in both groups at the start of the study (DAY 1), and at the end of the two-week period (DAY 14). There were no significant differences between group A and B, so the results are presented for the two groups combined. There was a significant increase in both pOSM and VAS during dehydration, and a significant fall in both variables during rehydration [F (9,99) = 18.69, p < 0.001, and F(9,99) = 11.25, p < 0.001, respectively]. Plasma AVP did not change significantly during either dehydration or rehydration [F (9,99) = 0.59, p = 0.8]. There were no significant differences in response for any of the three variables between DAY 1 and DAY 14. We conclude that elderly patients in long-term care exhibit changes in thirst and osmolality during dehydration and rehydration, and that these responses are reproducible. The lack of a significant AVP response requires further investigation.
authors.affiliation: Department of Geriatric Medicine, South Manchester University Hospitals NHS Trust, United Kingdom.
authors.forename: P A
authors.initials: PA
authors.lastname: O'Neill
authors.forename: J
authors.initials: J
authors.lastname: Duggan
authors.forename: I
authors.initials: I
authors.lastname: Davies
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001127:Arginine Vasopressin / Q000097:blood; D001835:Body Weight; D003681:Dehydration / Q000503:physiopathology*; D004326:Drinking; D006801:Humans; D008134:Long-Term Care; D009994:Osmolar Concentration; D013894:Thirst; D014556:Urine / Q000737:chemistry; D014882:Water-Electrolyte Balance
chemical_list: D001127:Arginine Vasopressin